Automotive aerodynamics is the study of aerodynamics of road vehicles. The main goals of the study are reducing drag and wind noise, minimizing noise emission, and preventing undesired lift forces and other causes of aerodynamic instability at high speeds. Additionally, the study of aerodynamics may also be used to achieve downforce in high-performance vehicles in order to improve vehicle traction, high speed stability, and cornering. The study is typically used to shape vehicle bodywork along with employing dedicated aerodynamic devices for achieving a desired compromise among the above characteristics for specific vehicle use.
A spoiler is an automotive aerodynamic device intended to “spoil” unfavorable air movement across a body of a vehicle in motion, usually described as turbulence or drag. Spoilers can be fitted at the front and/or at the rear of the vehicle body. Spoilers on the front of a vehicle are often called air dams. When the vehicle is in motion, in addition to directing air flow, such air dams also reduce the amount of air flowing underneath the vehicle which generally reduces aerodynamic lift and drag.
Additionally, when the vehicle is in motion, the flow of air at the rear of the vehicle becomes turbulent and a low-pressure zone is created, increasing drag and instability. Adding a spoiler at the rear of the vehicle body can help to delay flow separation from the body and a higher pressure zone created in front of the spoiler can help reduce lift on the vehicle body by creating downforce. As a result, in certain instances aerodynamic drag can be reduced and high speed stability will generally be increased due to the reduced rear lift.